Gauges - where the needles should sit!

[stanirish]

Changing MTFS

As the sensor is very hard to get at, any help on the easiest way to change this on a 91 S2 would be much appreciated. Many thanks in advance, Stan

[AndyP]

Remove the radiator, makes access much easier. If it looks like the original sensor I'd get a new plug and connectors too as they will be very corroded.

[dgacampbell]

Any update on these MTFS sensors yet?
Mine too sits at about 105 constantly with the new one,
Granted the car runs much better with the new one in.
question is would this be messing with my fueling in a 2.3 NG engined car?
TIA
Dan.

[DeS]

Ok Guys, forgive me this question. Is this picture and digits for real, or is it a nice joke? Been hearing different opinions about coolant temperature and just want not to change stat needlessly.

[UrS4boy]

Ok Guys, forgive me this question. Is this picture and digits for real, or is it a nice joke? Been hearing different opinions about coolant temperature and just want not to change stat needlessly.

It's not correct, at least not between 50C and 90C. This is closer to reality:

[A80Avant]

I have a question. Where do all the above stand when compared to the temp send or which sits at the back of the cylinder head? This one is read by the klima and in my case from vems.

As I use lower temp. Thermostat my dash gauge on cold days sits around the 60 degrees even though the cylinder head sensor reads 77-80 degrees.

[Bowie69]

It's not correct, at least not between 50C and 90C. This is closer to reality:

I'd agree with this!

On my CQ20V, the firs graduation is actually marked at 50C, and the 'normal' graduation is marked 90. The marks between them tally up as 60, 70 and 80 very neatly, and look exactly the same spacing as above.

The dash gauge is fed by the MFTS on the cylinder head outlet for a non-turbo, or on the water manifold on a turbo engine.

[Tridac]

Interesting thread. I had to run the car without an oil cooler for a while and definately noticed the difference on the motorway in summer. With the cooler, the oil temp never strays from the second major division, ie: between 60 and 130. Without the cooler, speed has to be limited to less than 80 to keep the needle at that level, so the cooler and thermostat seem to be doing their job. Water temp should be around the 95-100 mark. The system is pressurised, which raises the boiling point and for best efficiency engines should be run as hot as possible, within reason. Older 70's 3 litre BMW used to run at quite a high coolant pressure to allow a higher temp and were famous for blowing hoses when they got a bit older.

One of the things that really annoys me about the S2 temp gauges is that they are pretty cheap and cheerful and not that accurate. The temp gauge internals are just a heating element on a bimetal strip, which rotates a cam on the dial pointer. Would estimate +/-2-3 degrees at best accuracy when new and possibly much worse when the gauges get old and out of calibration. Added to which, the number of divisions between the calibated points doesn't add up to any integer division ratio, which makes it difficult to interpolate between major points, Fnally, the gauges are not linear. An irritating lack of precision all round, in fact.

Ok, engineer hat on there, but I guess sub degree accuracy isn't really needed for the application anyway. The key thing is that whatever values the gauges read when the engine is running right are noted, then any deviation from that could be an indication of a problem...